Domino to Office 365 email migration – timing, strategy and risk

An email migration consultant can help identify risk in your project.
An email migration consultant can help identify risk in your project.

When an organisation has been using IBM Domino and Lotus Notes for 10 years, there will be a number of business-critical Lotus Notes applications intricately woven into your organisation’s IT infrastructure.   These need to be considered carefully before embarking on your Domino to Office 365 email migration.

You know about Microsoft Office 365 and of other organisations who have migrated from Domino to Office 365 and believe you are ready to make this major change to your business.

Email is mission critical to the success of your organisation. If you commence an email migration project and experience technical issues, email may be unavailable for a period of time.

Today, we’ll look at how you can safely migrate from Domino to Office 365 and replace Lotus Notes with Outlook as the default email client by addressing three key points of an email migration strategy:

  • Timing
  • Strategy
  • Risk

Timing – Domino to Office 365 Migration?

What is the best time to migrate email from Domino to Office 365? There is no easy answer to this question.

However, you may wish to take into account the following factors:

Domino licencing: When does your licence deal end? It may be that you can time the end of your email migration project with IBM asking to renew your Domino server licences and your Lotus Notes client licences. It is likely that you can either not renew any licences, or at least renew a smaller licence footprint.

Quiet time: Is there a time when your business is not as busy, such as over the summer period? This would cause the least disruption to your business.

Related infrastructure project: There may be a new desktop rollout (eg: Windows 10) that you could choose to align the email migration project with. This is a good idea, as users will be impacted by getting used to a new desktop, so changing email from Lotus Notes to Outlook at this time may work for you.

Geographic office move: Your business may be moving to a new office location. This will be disruptive for users, but may be a good time to make the change from Lotus Notes to Outlook, as people will be expecting changes anyway due to moving to a different location.

The Office 365 email migration project will take place over a set period of time, and needs to allow for the phases of discovery, design, building, migration and support. Only certain points of the project are critical in terms of business risk.

Strategy – What is best Domino to Office 365 approach?

Migrating from Domino to Office 365 can be achieved using many different strategies. There is no single strategy that is better than all the others. Here are some strategies that we have used when consulting on Office 365 email migration projects.

  • Cutover

Your email migration takes place over a single weekend. Users on Friday are on Lotus Notes, and on Monday they are on Outlook. Overall, this is the simplest method of migrating, the least disruptive, and the least expensive. However, it can be viewed as high risk, as we’ll point out below. This option is not always available due to large amount of data to ingest into Office 365.

  • Phased

The email migration from Domino to Office 365 takes place over a few weeks, or months. Groups of mailboxes are migrated during this time, until everybody is migrated. This is a less-risky approach, but is more complex to achieve, as both Domino and Office 365 email systems will need to coexist together during the email migration.

  • Date Filter

Third-party email migration tools often provide a date filter function where the last 30 days of email is migrated only on the first pass. Then, the second pass migrates all mail older than 30 days. This option can help reduce the risks associated with a cutover approach. Users can be migrated over a weekend if only 30 days of emails are being migrated to Office 365. Older emails can be migrated over the next week, with users accessing them from their legacy Lotus Notes client.   For further information on approaching a Domino to Office 365 migration, read this blog article.

Risks – What are they and how can we help identify them?

What are the risks of migrating from Domino to Office 365 and replacing Lotus Notes with Outlook as the primary email client?

Imagine if email was unavailable for one day. What reaction would your business face, internally and from customers?

When replacing a core system with a new one, there are plenty of risks. But these risks can be mitigated. Managing risk effectively can be the difference between a successful email migration project and a failed email migration project.

One question to ask when consulting on an email migration project, is: “Please can I see the Risk Register?”.

Rarely does this result in a detailed, accurate Risk Register. If one were the CIO of a company whose Domino email system was being migrated to Office 365, you would want to see, and regularly review, the Risk Register.

On one email migration project, there was no Risk Register present, and the Project Manager refused to acknowledge the need for one.

Therefore, we put together our own Risk Register for them, which had one risk listed:

Risk 01: There is no Risk Register for this email migration project.
Risk Category: Critical.
Risk Impact: High – project more likely to fail through lack of managing Risk.
Mitigation: A Risk Register is created.

This was then shared with the CIO. The next day, the CIO instructed the Project Manager to compile and manage a Risk Register. The Risk Register then helped contribute towards their successful email migration project.


Timing, Strategy and Risk all have an important part to play in your email migration project to Office 365. Each factor is crucial to success, but maybe not equally vital. An email migration consultant can help you understand how these factors apply to your Domino migration to Office 365. Getting them right will go a long way towards ensuring your business can benefit from being on Outlook and Office 365.   For more information on what to consider for your email migration project, please read my Blog article covering typical challenges.

Contact us today to speak with an experienced consultant who can help with your Domino to Office 365 email migration project.

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